1. Field of the Invention
The present invention generally relates to a radio apparatus having multiple separate antennas, and in particular to a radio apparatus suitable for a portable transceiver or a portable receiver.
2. Description of the Related Art
In a radio apparatus having a pair of separate antennas providing spatial diversity, especially in a portable radio apparatus, it is difficult to ensure a sufficient spacing between the separate antennas, respectively. This causes isolation between antenna devices to be reduced, resulting in deterioration of antenna gain.
To overcome such a problem, a radio apparatus capable of selectively terminating the diversity antennas has been proposed in Japanese Patent Unexamined publication No. 7-202774. This conventional radio apparatus is provided with an antenna terminating system including a monopole antenna and a small size antenna which are connected to first and second antenna terminators through first and second switch devices, respectively. When the received signal level of the monopole antenna is higher than that of the small size antenna, the monopole antenna is connected to a receiver by the first switch device and the small size antenna is connected to the second antenna terminator by the second switch device. Otherwise, the monopole antenna is connected to the first antenna terminator by the first switch device and the small size antenna is connected to the receiver by the second switch device.